Apparatus for internally restoring a pipe

ABSTRACT

A method of internally restoring a pipe preferably includes the steps of isolating a leaking pipe from a system of pipes; drying an interior of a leaking pipe; measuring the airflow through the leak; cleaning the interior of the leaking pipe; presealing a leak with a leak sealing media, measuring the leak flow rate after the pre-sealing; applying an internal protective coating process; and pressure testing the leaking pipe for leaks. The pipe restoration method preferably uses a control box, a media injection system, an air compressor and a coating dispensing system at an inlet of the leaking pipe. The pipe restoration method preferably uses a coating overflow receiver, a muffler and a dust collector at an exit of the leaking pipe. After the treatments, the leaking pipe becomes a restored pipe. The restored pipe is pressure tested for leaks at a working pressure rating of the pipe.

This is a divisional application of nonprovisional application Ser. No.13/710,539 filed on Dec. 11, 2012, now U.S. Pat. No. 8,486,314, issuedon Jul. 16, 2013.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to pipes and more specificallyto an apparatus for internally restoring a pipe, which provides a costeffective alternative to replacing or making exterior repairs to thepipe.

2. Discussion of the Prior Art

A method of restoring small diameter pipe systems (the Process),utilizing compressed air for cleaning and internal coating pipes, hasbeen well known worldwide since at least the late 1970's. The ToyoLining Company received an approval from the Japanese government torestore water pipe systems in 1981. Since 1987, the Naval ResearchLaboratory has been involved in the development and testing of coatingsfor the in-place lining of piping systems. The process is commonly knownas the “Air-Sand” lining process and has been utilized by the Navy torestore and protect the piping in its ships and land-based facilities,both commercial and residential.

The real life application of the process to restore aging building watersystems has had many challenges. These challenges are well documentedwithin the US Navy report titled “Control of Lead in Drinking Water”from 1997 among others. The difficulty of insuring that the drysandblasting material is cleared from the pipe system after the cleaningoperation; restriction and plugging of pipe tee's and pipe intersectionswith excess coating material; and the inability of the process to sealleaks is well known to those in the art.

To seal other than the smallest of leaks in systems of pipes with theProcess has not been possible. Compressed air application of an internalliquid epoxy coating results in the coating being forced out the leakopening without sealing the leak. U.S. Pat. No. 6,739,950 to Krusestates in col. 6, lns. 51-52 that “If major leaks are discovered, arepair is performed prior to starting the pipe coating procedure.” TheNavy literature also teaches the repair of leaks before application ofinternal coatings.

More recently alternate methods for sealing leaks in systems of pipesinstalled within buildings have been taught. U.S. Pat. No. 5,622,209 toNaf discloses a process for sealing and internal repair of systems oflaid conduits. The Naf process is implemented by flooding the pipingsystem with water and a mixture of fillers including water swellablebentonite. If the known problem of clearing the dry cleaning mediaproved problematic in the prior art, the removal of the bentonite andfiller loaded solution suggested by Naf would be at least equally achallenge if not impossible. It will not be practical to clear a pipesystem once this material is introduced and allowed to set to the pointof sealing the leaks. The uncleared sealing media taught by Naf willnecessarily result in restricted and plugged pipe sections.

U.S. Pat. Nos. 7,858,149 and 8,033,242 to Gillanders et al. bothdisclose methods and systems for coating and sealing inside pipingsystems in one step. Claims are made that the addition of fiber andother fillers to the liquid coating material in ratios up to 50% byvolume will seal holes up to 0.125″ (⅛″) during the process of internalcoating of the pipe system. One skilled in the art understands thatduring the compressed air application of liquid epoxy to the inside of asmall diameter pipe any filler included in the liquid epoxy will beseparated by the action of the airflow and moved to the front of thelining stream. In the process of coating the inside of small diameterwater pipe systems in houses and commercial buildings, liquid coating isinjected with compressed air from multiple inlet points progressingtoward a single outlet. The individual “shots” of coating materialintroduced into each successive outlet are not measured to clear thesystem of pipes, just to coat an individual portion of the system, thusthe filler load of each “shot” of coating will remain within the systemcausing a significant reduction in internal pipe diameter, compromisethe intended lining thickness, and result in an inferior finishedproduct.

Accordingly, there is a clearly felt need in the art for an apparatusfor internally restoring a leaking pipe, which provides a cost effectivealternative to replacing or making exterior repairs to a pipe, and whichutilizes airflow measurements and airflow control inside a pipe tooptimize the repair of a leak with the application of an internalrestoration coating.

SUMMARY OF THE INVENTION

The present invention provides an apparatus for internally restoring apipe, which utilizes airflow measurements inside a pipe to optimize theprocesses of leak sealing and application of the internal protectivecoating. A method of internally restoring a leaking pipe (piperestoration method) preferably includes the steps of separating aleaking pipe from a system of pipes, drying an interior surface of aleaking pipe; measuring the airflow through the leak; cleaning theinterior surface of the leaking pipe; pre-sealing a leak with a dry leaksealing process, measuring the leak flow rate after the pre-sealing;applying an internal protective coating; and pressure testing theleaking pipe for leaks.

The pipe restoration method preferably uses an air compressor, an airdryer, a control box, a media injection device and a coating injectionsystem at an inlet of the leaking pipe. The pipe restoration methodpreferably uses a coating overflow receiver, a test valve, a muffler anda dust collector at an exit of the leaking pipe. The control boxpreferably includes a plurality of process control and measuringcapabilities including an airflow meter, multiple airflow controlvalves, an inlet pressure gauge, an outlet pressure gauge, inlineheating elements, a process heat controller and various safety featuresfor protection from overheat and overpressure. The media injectiondevice includes a media reservoir, a media introduction control valve,an air inlet, an air outlet and a flexible system connection assembly.The air dryer includes a radiator, a fan, a water separator and a heatexchanger. The air compressor and the liquid coating dispensing systemboth can be purchased from any number of manufacturers.

The air compressor is connected to an air inlet of the air dryer; anoutlet of the air dryer is connected to the inlet of the control box;and the outlet of the control box is connected to an air inlet of theclear inlet tube. The clear inlet tube is preferably inserted before aninlet of the leaking pipe. The media injection device and the coatinginjection system are preferably installed between the outlet of thecontrol box and inlet of the clear inlet tube. The interior surface ofthe leaking pipe is dried by the flow of heated compressed air deliveredthrough the control box.

The airflow through a leak is measured with the air flow meter in thecontrol box. The interior surface of the leaking pipe is cleaned byflowing sand blast media through the leaking pipe, which is dispensed bythe media injection device. The leak in the leaking pipe is pre-sealedby injecting a dry leak sealing media into the air stream with the mediainjection device. The airflow rate through the leak in the pipe ismeasured, after completion of the pre-sealing process, with the controlbox. The pre-sealing with dry leak-sealing media and airflow rate arerepeatedly measured, until the airflow rate through the leak in the pipeis reduced below the requirement for the internal coating process. Aplug of liquid coating is injected into the clear inlet tube with thecoating injection device and forced through an interior surface of theleaking pipe with air from the air compressor. The control box heatsairflow and controls a volume of airflow from the air compressor. Excessliquid coating is caught in the coating overflow receiver at an outletof the leaking pipe. The air exiting the restored pipe is filtered withthe dust collector and the sound of the air exiting the leaking pipe ismuffled with a muffler. After the treatments, the leaking pipe becomes arestored pipe. The restored pipe is pressure tested for leaks at aworking pressure rating for the restored pipe. Finally, the restoredpipe is reconnected to its piping system.

OBJECTIVES OF THE INVENTION

Accordingly, it is an objective of the present invention to provide apipe restoration method, which provides a cost effective alternative toreplacing or making exterior repairs to a pipe located within theconcrete floors, or wall systems, of buildings.

It is another objective of the present invention to provide a piperestoration method, which determines the size of a leak in a pipe.

It is a further objective of the present invention to provide a piperestoration method, which surveys a pipe for existing damage thatrestricts flow through the pipe.

It is yet a further objective of the present invention to provide a piperestoration method for internally cleaning a pipe.

It is yet a further objective of the present invention to provide a piperestoration method, which pre-seals a leak with dry leak sealing mediacontaining metal fibers and flakes within a blend of cellulose fibers.

It is yet a further objective of the present invention to provide a piperestoration method, which precisely measures and controls the volume ofairflow through a pipe.

It is yet a further objective of the present invention to provide a piperestoration method, which precisely controls the temperature of theairflow through a pipe.

It is yet a further objective of the present invention is to provide apipe restoration method, which applies an internal protective coating toa pipe wherein the application of the coating is regulated by precisecontrol of airstream volume and temperature.

It is a final objective of the invention is to provide methods, systemsand devises to force the cure of the internal protective coating with aheated airflow.

These and additional objects, advantages, features and benefits of thepresent invention will become apparent from the following specification.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a flow chart of a pipe restoration method in accordance withthe present invention.

FIG. 2 is a schematic diagram of a pipe restoration method in accordancewith the present invention.

FIG. 3 is a schematic diagram of a control box of a pipe restorationmethod in accordance with the present invention.

FIG. 4 is a schematic diagram of an injection system of a piperestoration method in accordance with the present invention.

FIG. 5 is a schematic diagram of an air dryer of a pipe restorationmethod in accordance with the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

With reference now to the drawings, and particularly to FIG. 1, there isshown a flow chart of a pipe restoration method 1. With reference toFIG. 2, the pipe restoration system 1 has been found to be satisfactoryin repairing a leaking pipe 100, which is a part of a system of pipesfor carrying pressurized water in a building. The leaking pipe 100 iscommonly encased with a concrete foundation or floor of the building.The leaking pipe is typically a soft copper water pipe experiencingpinhole leaks due to internal pitting corrosion and the leaking pipe 100is between ½″ and 2″ in diameter. However, the pipe restoration method 1should not be limited to the previously recited parameters.

With reference to FIGS. 3-4, the pipe restoration method 1 preferablyincludes the steps of separating a leaking pipe from a system of pipesin process block 10, drying an interior surface of a leaking pipe inprocess block 11; measuring the airflow through the leak in processblock 12; cleaning an interior surface of the leaking pipe in processblock 14; pre-sealing a leak with a dry leak sealing media in processblock 16, measuring the leak flow rate after the pre-sealing in processblock 18; applying an internal coating in process block 20; and pressuretesting the leaking pipe for leaks in process block 22. The leaking pipe100 is isolated from the system of pipes by opening wall surfaces in thebuilding, where the pipe exits the foundation at each end of the pipeand dissecting the connection manifolds to expose the ends to receivethe restoration process.

The pipe restoration method 1 preferably uses a control box 24, a mediainjection system 26, an air compressor 28, an air dryer 29, a coatingdispensing system 30 and a clear inlet tube 32 at an inlet of theleaking pipe 100. The compressor preferably generates airflow with apressure up to 175 psi at a flow rate of 375 cfm. The pipe restorationmethod 1 also preferably includes a clear exit tube 34, a coatingoverflow receiver 36, a test valve 38, a muffler 40 and a dust collector42 at an outlet of the leaking pipe 100. The control box 24 preferablyincludes an air inlet 44, a plurality of air flow control valves, twopressure gages, an air flow meter 46, a flow switch 48, a heater unit 50and an air outlet 52. The heater unit 50 includes a tube heater 54, aheater controller 56 and a thermocouple 58. An output of the aircompressor 28 is connected to the compressed air inlet 44. A firstpressure gage 60 measures the pressure of the air from the aircompressor 28. A control valve 62 may be used to shut-off airflowthrough control box 24.

A control bleed valve 64 allows excess air to be bled from the controlbox 24. An air volume flow valve 66 is used to control the volume of airtraveling through the leaking pipe 100. A second pressure gage 68 isused to measure the pressure of the airflow at the output of the airvolume flow valve 66. The air flow meter 46 provides a reading of thevolume of airflow (preferably measured in cubic feet per minute (cfm)flowing from the air volume flow valve 66. The heater controller 56operates the tube heater 54 based on feedback from the thermocouple 58.The flow switch 48 is operated by the heater controller 56. The flowswitch 48 detects an airflow interruption. The heater controller 56turns-off the heater unit 50 if an airflow interruption occurs.

The media injection device 26 includes an air inlet 70, a mediareservoir inlet 72, a media valve 74, a media reservoir 75, a mediaoutlet 76 and a flow tube 78. The air inlet 70 is connected to theoutlet 52 of the control box 24 during the cleaning and pre-sealingoperations. The control valve 66 controls airflow through the mediainjection device 26. Sand blast media is poured into the media reservoirinlet 72. The sand blast media flows into the media reservoir 75 andthen the media valve 74 is opened. The sand blast media flows into theflow tube 78 and is transported through the media injection device 26 byairflow from the control box 26. The sand blast media preferably 23-30garnet for copper water lines. The media reservoir 74 is filled withmedia for cleaning and pre-sealing an inside of the leaking pipe 100.The media outlet 76 is coupled to one end of the clear inlet tube 32. Anoutlet of the coating dispensing system 30 is coupled to the one end ofthe clear inlet tube 32. Both the air compressor 28 and the coatingdispensing system 30 can be purchased from any number of manufacturers.

With reference to FIG. 5, the air dryer 29 preferably includes aradiator 80, a fan 82, a water separator 84 and a heat exchanger 86. Theair compressor 28 is connected to an air inlet 88 of the air dryer 29;an outlet 90 of the air dryer 29 is connected to the inlet 44 of thecontrol box 24; and the outlet 52 of the control box 29 is connected toan air inlet of the clear inlet tube 32. The clear inlet tube 32 ispreferably inserted before an inlet of the leaking pipe 100. The mediainjection device 26 is preferably installed between the outlet of thecontrol box 24 and inlet of the clear inlet tube 32.

The other end of the clear inlet tube 32 is connected to an inlet of theleaking pipe 100. One end of the clear exit tube 34 is connected to anoutlet of the leaking pipe 100. The other end of the clear exit tube 34is coupled to the coating overflow receiver 36 and an inlet of the testvalve 36. An outlet of the test valve 38 is connected to the muffler 40and the dust collector 42. Excess liquid coating material and leaksealing media is caught in the coating overflow receiver 36. The airexiting the leaking pipe 100 is filtered with the dust collector 42 andthe sound of the air exiting the leaking pipe is muffled with a muffler40.

To begin the repair process, the leaking pipe 100 is isolated from thebuilding or other piping systems in building in process block 10. Theinterior surface of the leaking pipe 100 is dried by flowing drycompressed air through the control box 24 in process block 11. Atemperature of the air is preferably between 100° F. and 130° F. and theairflow volume is up to 250 cfm for a 2¼ inch diameter pipe. The tubeheater 24 heats the compressed air. Airflow through the leaking pipe 100is measured by the airflow meter 46 in the control box 24 and by closingthe test valve 38 in process block 12. A dry leak sealing media ischosen based on air volume flow readings. The dry leak-sealing mediapreferably includes a mixture of cellulose fibers combined with finemetal fibers and metal flakes. The interior surface of the leaking pipe100 is cleaned by injecting sand blast media there through in controlledbursts from the media injection device 26 in process block 14.

The leak in the leaking pipe 100 is pre-sealed by injecting the selecteddry leak sealing media with the media injection device 26 in processblock 16. The flow rate through the leak in the leaking pipe 100 ismeasured with the airflow meter 46 and by closing the test valve 38 inprocess block 18. In decision block 15, if the volume of airflow throughthe leak is reduced below the requirement for the liquid coatingapplication then proceed to process block 20, if not repeat thepre-sealing in process block 16.

A liquid corrosion protection coating is applied in process block 20.The coating is preferably a plural component liquid epoxy, but othersubstances may also be used. The coating is certified for contact withdrinking water when used in water pipes. The coating is applied byinjecting a metered amount of coating at a specific airflow rate andtemperature, selected for the leaking pipe 100, based on an innerdiameter of the leaking pipe 100. The liquid coating is dispensed as a“plug” or “shot” of material into the clear inlet tube 32 in a volumecalculated to ensure that the entire inner perimeter of the leaking pipe100 is coated and excess fillers and coating material are carried intothe coating overflow receiver 36. The liquid coating may contain up to2% by weight of various glass fibers and flake fillers dependent on thereduced leak airflow measurements. The liquid coating is force cured toa test hardness by airflow heated by the tube heater 54. A temperatureof the liquid coating is controlled by the heater control 56, and theairflow is regulated by the airflow control valve 66, until the testhardness is obtained. The liquid coating is pre-heated beforeintroduction into the leaking pipe to a temperature preferably between100° F. and 130° F. to control the viscosity thereof. The liquid coatingintroduced into the leaking pipe 100 is determined by a pipe length anda specified coating thickness. The liquid coating may contain fillers ofup to 2% glass fibers and flakes by weight as a sealant for small holes.The liquid coating is applied to the inside diameter of the leaking pipe100 with a stream of air. The stream of air is heated to a preferabletemperature of between 100° F. and 130° F. The precise temperature ofthe air stream is determined by the type of liquid coating. The controlbox 24 provides a preferable flow rate of the air stream between 0.05and 375 cfm. The flow rate of the air stream is determined by acombination of pipe diameter and liquid coating selection.

Using hot air forced cure reduces the time to obtain test hardness. Atemperature of the forced air is preferably between 100° F. and 130° F.with a volume of air preferably between 10 CFM and 40 CFM as controlledby the control box 24. For example, a cure time for a specified epoxycoating at room temperature (72 degrees) takes 6 hours. Flowing heatedair through an interior surface of the coated leaking pipe 100 will heatthe liquid epoxy coating and reduce the cure time. For each 10° C. thecoating is heated above 72° F., the cure time to testing hardness isreduced by 50%.

The leaking pipe 100 is now a restored pipe 100. The restored pipe 100is pressure tested for leaks at the working pressure rating of the pipein process block 22 by closing the test valve 38 and measuring thepressure on the second pressure gage 68. In decision block 25, if therestored pipe 100 passes the pressure test, the restored pipe 100 isrestored to service per the liquid coating “return to service”guidelines and the process is ended. If the restored pipe 100 fails thepressure test, the liquid coating process in process block 20 isrepeated per liquid coating “film thickness” specifications.

While particular embodiments of the invention have been shown anddescribed, it will be obvious to those skilled in the art that changesand modifications may be made without departing from the invention inits broader aspects, and therefore, the aim in the appended claims is toover all such changes and modifications as fall within the true spiritand scope of the invention.

We claim:
 1. An apparatus for internally restoring a pipe, comprising:an air compressor having output; an air dryer having an inlet and anoutlet, said output of said air compressor is connected to said inlet ofsaid air dryer; a control box having an inlet, outlet, a flow switch, atube heater, a heater controller and an air flow meter, said air flowmeter measuring the volume of air passing through said control box, saidinlet of said control box is connected to an outlet of said air dryer,said tube heater heats air passing through said control box, said heatercontroller operates said flow switch, said flow switch is not opened bysaid heater controller unless a temperature of air in said control boxis above a preset temperature; a media injection device for injectingdry sealing media, said media injection device includes an inlet and anoutlet, said inlet of said media injection device is connected to saidoutlet of said control box; and a coating dispenser system includes anoutlet, a coating material being dispensed through said outlet, saidoutlet of said control box, said media injection device and said coatingdispensing system are connected to an inlet of a pipe to be restored,wherein said air compressor propels the dry sealing media through thepipe to be restored.
 2. The apparatus for internally restoring a pipe ofclaim 1, further comprising: a clear inlet tube is inserted between theinlet of the pipe to be restored and said outlet of said control box,said media injection device and said coating dispensing system.
 3. Theapparatus for internally restoring a pipe of claim 1, furthercomprising: a clear exit tube is connected to an outlet of the pipe tobe restored.
 4. The apparatus for internally restoring a pipe of claim 1wherein: said control box includes at least one valve.
 5. The apparatusfor internally restoring a pipe of claim 1 wherein: said control boxincludes at least one pressure gage.
 6. The apparatus for internallyrestoring a pipe of claim 3, further comprising: an overflow receiver isconnected to said clear outlet tube.
 7. An apparatus for internallyrestoring a pipe, comprising: an air compressor having output; an airdryer having an inlet and an outlet, said output of said air compressoris connected to said inlet of said air dryer; a control box having aninlet, outlet, an air flow meter, a tube heater, a heater controller, aflow switch and at least one valve, said air flow meter measuring thevolume of air passing through said control box, said inlet of saidcontrol box is connected to an outlet of said air dryer, said flowswitch controlling the flow of air through said control box, said tubeheater heats air passing through said control box, said heatercontroller operates said flow switch, said flow switch is not opened bysaid heater controller unless a temperature of air in said control boxis above a preset temperature; a media injection device for injectingdry sealing media, said media injection device includes an inlet and anoutlet, said inlet of said media injection device is connected to saidoutlet of said control box; and a coating dispenser system includes anoutlet, said outlet of said control box, a coating material beingdispensed through said outlet, said media injection device and saidcoating dispensing system are connected to an inlet of a pipe to berestored, wherein said air compressor propels the dry sealing mediathrough the pipe to be restored.
 8. The apparatus for internallyrestoring a pipe of claim 7, further comprising: a clear inlet tube isinserted between the inlet of the pipe to be restored and said outlet ofsaid control box, said media injection device and said coatingdispensing system.
 9. The apparatus for internally restoring a pipe ofclaim 7, further comprising: a clear exit tube is connected to an outletof the pipe to be restored.
 10. The apparatus for internally restoring apipe of claim 7 wherein: said control box includes at least one pressuregage.
 11. The apparatus for internally restoring a pipe of claim 9,further comprising: an overflow receiver is connected to said clearoutlet tube.
 12. An apparatus for internally restoring a pipe,comprising: an air compressor having output; an air dryer having aninlet and an outlet, said output of said air compressor is connected tosaid inlet of said air dryer; a control box having an inlet, outlet, anair flow meter, a flow switch, a tube heater, a heater controller and atleast one pressure gage, said air flow meter measuring the volume of airpassing through said control box, said inlet of said control box isconnected to an outlet of said air dryer, said tube heater heating airflowing through said control box, said heater controller operates saidflow switch, said flow switch is not opened by said heater controllerunless a temperature of air in said control box is above a presettemperature; a media injection device for injecting dry sealing media,said media injection device includes an inlet and an outlet, said inletof said media injection device is connected to said outlet of saidcontrol box; and a coating dispenser system includes an outlet, saidoutlet of said control box, a coating material being dispensed throughsaid outlet, said media injection device and said coating dispensingsystem are connected to an inlet of a pipe to be restored, wherein saidair compressor propels the dry sealing media through the pipe to berestored.
 13. The apparatus for internally restoring a pipe of claim 12,further comprising: a clear inlet tube is inserted between the inlet ofthe pipe to be restored and said outlet of said control box, said mediainjection device and said coating dispensing system.
 14. The apparatusfor internally restoring a pipe of claim 12, further comprising: a clearexit tube is connected to an outlet of the pipe to be restored.
 15. Theapparatus for internally restoring a pipe of claim 12 wherein: saidcontrol box includes at least one valve.